Protecting device for electric circuits.



R. P. JACKSON. IRCTECTING DEVICE FOR ELECTRIC CIRCUITS.

, APPLICATION FILED 111111.13, 1911.

Patented Jan. 7, 1918.

Ci y IN NTOR ATTORNEY RAY 1 JACKSON, or nzoenwoon PARK,

PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OI PIE:bl'NSYLVAN'IA..

PROTECTING DEVICE FOR ELECTRIC CIRCUITS.

To all wkome't may concern.-

Be it known that I. RAY P. JACKSON, a

- citizen of the United States, and aresident Protecting which thetributing and lighting of Edgewood Park. in gbeny and State of Pennsylvania, have invented a new and useful Improvement in Devices for Electric Circuits, of following is a specification- My invention relates to protecting devices for electric circuits, and it has particular reference .to devices which are employed in connection with the usual low-voltage dissystems for the purpose of preventing the maintenance of excessive and injurlous voltages thereon.

The object of my invention is to provide a simple and inexpensive device of the above-indicated character which shall be durable in construction, effective and reli able in operation and particularly adapted. to establish a permanent ground connection in case a low-voltage distributing system is crossed by a foreign system carrying an excessive and injurious voltage.

It has been customary, in distributing and lighting systems, to provide protective means for temporarily grounding the system in case of a lightning discharge or the existence of an abnormal voltage thereon.

owever, no provision has been made for establishing a permanent ground connection, and such protective devices have frequently been rendered ineffective or have been destroyed upon the occurrence of severe discharges or of discharges of long duration. Under these circumstances, the distributing system is provided with no. protection against abnormal. voltages, and severe injuries have sometimes been sustained by persons who have accidentally come into contact with the conductors of the system. Y

According to my invention, I provide means for permanently grounding the system in. case of a. cross, and thus prevent a maintenance of voltages in excess of the normal operating voltage upon the system, So that danger of personal injuries is eliminated.

My invention may best be understood by reference to the accompanying drawing in Which- Figure 1 is a diagrammatic view of a system embodying my invention. I Fig. 2 is a plan 'VIBW of a device constructed in ac- Specification of Letters Patent.

Application filed March 13, 1911. Serial No. 614,848.

the county of Alle- Patented Jan. 7,1913.

cordance with my invention, and Fig. 3 is a view, partially in elevation and partially in section, of the device shown in Fig. 2.

Referring to the drawings, a supply circuit 12 supplies energy to a primary \vinding'3 of a distributing transformer 4, the secondary winding 5 thereof being adapted to deliver energy to a plurality of lamps or other translating devices 6 through a distributing circuit 78. The conductors 7 and 8 of the distributing circuit are severally provided with suitable fuses 9, or other circuit interrupting devices, and are grounded through av protecting device 10 which con titutes my invention.

The protecting device 10 comprises a supporting member or plate 11 and a plurality of electrodes 12. The supporting member 11 is made of insulating material and is provided with a recess 13 in its upper surface. The electrodes 12 are of like construction and each comprises a tubular or cylindrical member 14 of suitable conducting material and a capmember 15 which forms the upper part of the electrode, and by means of which the electrode is secured in position through the agency of a centrally disposed bolt 16 and suitable nuts 17.- A body 18 of readily fusible and conducting material is disposed within the tubular member 14. and constitutes the core of the electrode. The electrodes 12 and their associated cores 18 are supported on raised annular members 19 having communicating openings or recesses 20, said electrodes 12 being disposed on end and arranged side by side a slight distance apart to form a suitable discharge gap, as will be readily understood.

My invention is not restricted to the use of two electrodes only, as a larger number of such members may be employed in a similar manner and for a similar purpose.

Assuming that a foreign high-voltage system (not shown) comes into contact with or crosses the conductor 7 of the lowof the device is as follows: It is evident that the high voltage of the foreign system is impressed upon the distributing system and hence a discharge across the gap of the protecting device 10 is effected, whereby a temporary ground connection is made. Thus, the conductor 7 is subjected to ground potential and no abnormal voltage can exist voltage distributing system, the operation system, although its normal v operation I is cross? continues and a severe discharge of considerable duration is maintained between the electrodes 12 of the protecting device 10, the heat generated therein becomes SUillClQIltto melt the readily fusible cores 18 of the electrodes. The fusible material then runs down into the recess 13 in the supporting member 11 and through the communicating openings 20 in the annular raised portions 19 to electrically connect the two electrodes, thereby establishing a permanent ground connection which renders the distributing system harmless. If the cross occurs upon the conductor 8 of the distributing system, a similar ground connection is effected by its associated protecting device 10, as will be readily understood. In case the cross occurs on 8, suitable ground lished through the protecting devices 1 0 in a manner similar to that hereinbefore described. Thus, the secondary winding 5 of the transformer t is short circuited and fuses 9 blown, thereby segregating the conductors 7 and 8 from the main distributing system. However, inasmuch as these conductors are pe manently grounded through the protecting devices 10, they are maintained at-ground potential and no injury can be sustained by a person coming into accidental contact =therewith.

If protecting devices such as have heretofore been employed, which were not pro vided with any means for permanently bridging the gap in case of severe discharges between the electrodes, had been used, the discharges would hav been maintained until the electrodes were damaged or destroyed. The segregated portion of the distributing system would then have been unprotected by, suitable ground connections and the high voltage of the foreign system would have existed thereon. It is evident, therefore, that, by the use of the protecting devices which I have devised, the distributing system cannot be subjected to abnormal rises in volt-age and no personal injuries can occur by reason of accidental cont act therewith.

Such modifications in the structural despaced cylindrical electrodes both the conductors 7 and connections are estabterial disposed within the spirit and scope of my invention.

I claim as my invention:

1. In a protective device for electric circuits, the combination with a plurality of dis osed sideby-side, and bodies of readil usible material normally disposed wit in said electrodes, of a receptacle associated therewith for receiving said material, when melted, and retaining it in electrical contact with said electrodes.

2. In a protective device for electric circuits, the combination with a supporting member, and a plurality of cylindrical electrodes mountedthercon and spaced one from another, of cores of readily fusible conducting material for said electrodes, said supporting member having communicating recesses for said fusible material, when melted, to electrically connect said electrodes.

3. In a protective device for electric circuits comprising a supporting member having a recess therein, a plurahtyof cylindrical electrodes mounted on endin said recess and spaced slightly apart to form a discharge gap, bodies of readily fusible mawithin said electrodes, and means for permitting said material, when melted, to run into said recess and bridge said gap.

' 4. The combination with an electric circuit, and a suitable ground connection therefor having a discharge gap comprising two vertical electrodes each of which has a core of readily fusible conducting material, of an insulating basefor said electrodes having a channel to receive the core material when fused.

In testimony whereof, I have hereunto subscribed my name this 28th day of Feb., 1911.

RAY P. JACKSON.

Witnesses D. A. BOWEN, B. B. HINES.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, twashington, D. 6. 

